1. Field of the Invention
The present invention relates to an elevator which includes a machine room having only an area equivalent to a horizontal cross-sectional area of an elevator shaft, but in which a large operation space required for a maintenance of an elevator hoist, a control panel, a speed governor, and so on, can be secured, without needing an additional receiving beam on a building side for installing an elevator hoist.
2. Background Art
A machine room is conventionally disposed above an elevator shaft in which a cage and a counterweight of an elevator are vertically moved. An elevator hoist, a control panel, a speed governor, and so on are disposed in the machine room (see Japanese Patent Laid-Open Publication No. 175776/1996 (FIGS. 6 and 7)). For example, in a machine room 1 of a conventional elevator shown in FIG. 25, an elevator hoist 2 is disposed in a center part of the machine room 1, a control panel 3 is disposed along a left wall 1a, and a speed governor 4 is disposed along a back wall 1b. 
A not-shown cage and a counterweight are suspended like a jig back by a main rope 5 passing round a traction sheave 2a and a deflecting sheave 2b which are driven in rotation by the elevator hoist 2.
A machine bed 6 on which the elevator hoist 2 is mounted is supported by three machine beams 8 which extend horizontally in the right and left direction in the drawing, through rubber cushions 7a and 7b. 
These machine beams 8 are supported by building-side receiving beams 10a and 10 which extend perpendicularly to a plane of the drawing, through upward rising machine beams 9a and 9b (see, for example, Japanese Patent Laid-Open Publication No. 79624/1999 (FIG. 7)).
In the conventional elevator shown in FIG. 25, the elevator hoist 2 is arranged in a center part of the machine room 1 for suspending the cage and the counterweight.
Thus, an operation space required for maintenance of the elevator hoist 2, the control panel 3, the speed governor 4, and so on, is arranged to surround the elevator hoist 2. In this constitution, it is possible to secure a sufficient dimension required for the maintenance operation.
However, the Japanese law relating to buildings and a regulation for ensuring safety of elevators are different from those of foreign countries. Some countries require a unified operation space having a certain minimum area for maintenance carried out in a machine room.
In this case, the arrangement of the operation space which surrounds the elevator hoist 2 does not satisfy safety regulations in such countries. Thus, a machine room having a floor area larger than a horizontal cross-sectional area of an elevator shaft is needed.
On one hand, in the conventional elevator shown in FIG. 25, the control panel 3 must be arranged along an extension of the machine beams 8 because of a layout restriction of the machine room 1.
Thus, it is impossible to elongate ends of the machine beams 8 to a building-side receiving beam 10c disposed in a lower part of the left wall 1a, so that the receiving beam 10a must be additionally disposed on the building side.
On the other hand, as shown in FIG. 26, in order to elongate the ends of the machine beams 8 to the building-side receiving beam 10c disposed in a lower part of the left wall 1a, the control panel 3 must be mounted on the machine beams 8, and an operation base 11 must be installed to secure an operation space for maintenance of the control panel 3.
In this situation, there may be the case in which a size of the control panel 3 must be limited in a height direction thereof, in order that an upper part of the control panel 3 and a ceiling of the machine room 1 do not interfere with each other.